#include "zuc.h"

/* S-boxes */
unsigned char ZUC::S0[256] = {
    0x3e,0x72,0x5b,0x47,0xca,0xe0,0x00,0x33,0x04,0xd1,0x54,0x98,0x09,0xb9,0x6d,0xcb,
    0x7b,0x1b,0xf9,0x32,0xaf,0x9d,0x6a,0xa5,0xb8,0x2d,0xfc,0x1d,0x08,0x53,0x03,0x90,
    0x4d,0x4e,0x84,0x99,0xe4,0xce,0xd9,0x91,0xdd,0xb6,0x85,0x48,0x8b,0x29,0x6e,0xac,
    0xcd,0xc1,0xf8,0x1e,0x73,0x43,0x69,0xc6,0xb5,0xbd,0xfd,0x39,0x63,0x20,0xd4,0x38,
    0x76,0x7d,0xb2,0xa7,0xcf,0xed,0x57,0xc5,0xf3,0x2c,0xbb,0x14,0x21,0x06,0x55,0x9b,
    0xe3,0xef,0x5e,0x31,0x4f,0x7f,0x5a,0xa4,0x0d,0x82,0x51,0x49,0x5f,0xba,0x58,0x1c,
    0x4a,0x16,0xd5,0x17,0xa8,0x92,0x24,0x1f,0x8c,0xff,0xd8,0xae,0x2e,0x01,0xd3,0xad,
    0x3b,0x4b,0xda,0x46,0xeb,0xc9,0xde,0x9a,0x8f,0x87,0xd7,0x3a,0x80,0x6f,0x2f,0xc8,
    0xb1,0xb4,0x37,0xf7,0x0a,0x22,0x13,0x28,0x7c,0xcc,0x3c,0x89,0xc7,0xc3,0x96,0x56,
    0x07,0xbf,0x7e,0xf0,0x0b,0x2b,0x97,0x52,0x35,0x41,0x79,0x61,0xa6,0x4c,0x10,0xfe,
    0xbc,0x26,0x95,0x88,0x8a,0xb0,0xa3,0xfb,0xc0,0x18,0x94,0xf2,0xe1,0xe5,0xe9,0x5d,
    0xd0,0xdc,0x11,0x66,0x64,0x5c,0xec,0x59,0x42,0x75,0x12,0xf5,0x74,0x9c,0xaa,0x23,
    0x0e,0x86,0xab,0xbe,0x2a,0x02,0xe7,0x67,0xe6,0x44,0xa2,0x6c,0xc2,0x93,0x9f,0xf1,
    0xf6,0xfa,0x36,0xd2,0x50,0x68,0x9e,0x62,0x71,0x15,0x3d,0xd6,0x40,0xc4,0xe2,0x0f,
    0x8e,0x83,0x77,0x6b,0x25,0x05,0x3f,0x0c,0x30,0xea,0x70,0xb7,0xa1,0xe8,0xa9,0x65,
    0x8d,0x27,0x1a,0xdb,0x81,0xb3,0xa0,0xf4,0x45,0x7a,0x19,0xdf,0xee,0x78,0x34,0x60
};

unsigned char ZUC::S1[256] = {
    0x55,0xc2,0x63,0x71,0x3b,0xc8,0x47,0x86,0x9f,0x3c,0xda,0x5b,0x29,0xaa,0xfd,0x77,
    0x8c,0xc5,0x94,0x0c,0xa6,0x1a,0x13,0x00,0xe3,0xa8,0x16,0x72,0x40,0xf9,0xf8,0x42,
    0x44,0x26,0x68,0x96,0x81,0xd9,0x45,0x3e,0x10,0x76,0xc6,0xa7,0x8b,0x39,0x43,0xe1,
    0x3a,0xb5,0x56,0x2a,0xc0,0x6d,0xb3,0x05,0x22,0x66,0xbf,0xdc,0x0b,0xfa,0x62,0x48,
    0xdd,0x20,0x11,0x06,0x36,0xc9,0xc1,0xcf,0xf6,0x27,0x52,0xbb,0x69,0xf5,0xd4,0x87,
    0x7f,0x84,0x4c,0xd2,0x9c,0x57,0xa4,0xbc,0x4f,0x9a,0xdf,0xfe,0xd6,0x8d,0x7a,0xeb,
    0x2b,0x53,0xd8,0x5c,0xa1,0x14,0x17,0xfb,0x23,0xd5,0x7d,0x30,0x67,0x73,0x08,0x09,
    0xee,0xb7,0x70,0x3f,0x61,0xb2,0x19,0x8e,0x4e,0xe5,0x4b,0x93,0x8f,0x5d,0xdb,0xa9,
    0xad,0xf1,0xae,0x2e,0xcb,0x0d,0xfc,0xf4,0x2d,0x46,0x6e,0x1d,0x97,0xe8,0xd1,0xe9,
    0x4d,0x37,0xa5,0x75,0x5e,0x83,0x9e,0xab,0x82,0x9d,0xb9,0x1c,0xe0,0xcd,0x49,0x89,
    0x01,0xb6,0xbd,0x58,0x24,0xa2,0x5f,0x38,0x78,0x99,0x15,0x90,0x50,0xb8,0x95,0xe4,
    0xd0,0x91,0xc7,0xce,0xed,0x0f,0xb4,0x6f,0xa0,0xcc,0xf0,0x02,0x4a,0x79,0xc3,0xde,
    0xa3,0xef,0xea,0x51,0xe6,0x6b,0x18,0xec,0x1b,0x2c,0x80,0xf7,0x74,0xe7,0xff,0x21,
    0x5a,0x6a,0x54,0x1e,0x41,0x31,0x92,0x35,0xc4,0x33,0x07,0x0a,0xba,0x7e,0x0e,0x34,
    0x88,0xb1,0x98,0x7c,0xf3,0x3d,0x60,0x6c,0x7b,0xca,0xd3,0x1f,0x32,0x65,0x04,0x28,
    0x64,0xbe,0x85,0x9b,0x2f,0x59,0x8a,0xd7,0xb0,0x25,0xac,0xaf,0x12,0x03,0xe2,0xf2
};

/* D constants */
unsigned int ZUC::EK_d[16] = {
    0x44D7, 0x26BC, 0x626B, 0x135E, 0x5789, 0x35E2, 0x7135, 0x09AF,
    0x4D78, 0x2F13, 0x6BC4, 0x1AF1, 0x5E26, 0x3C4D, 0x789A, 0x47AC
};

unsigned int ZUC::AddM(unsigned int a, unsigned int b) {
	unsigned int c = a + b;
	return (c & 0x7FFFFFFF) + (c >> 31);
}

#define MulByPow2(x, k) ((((x) << k) | ((x) >> (31 - k))) & 0x7FFFFFFF)

/* LFSR */
void ZUC::LFSRWithInitializationMode(unsigned int u) {
    unsigned int f, v;

    f = LFSR_S[0];
    v = MulByPow2(LFSR_S[0], 8);
    f = AddM(f, v);

    v = MulByPow2(LFSR_S[4], 20);
    f = AddM(f, v);

    v = MulByPow2(LFSR_S[10], 21);
    f = AddM(f, v);

    v = MulByPow2(LFSR_S[13], 17);
    f = AddM(f, v);

    v = MulByPow2(LFSR_S[15], 15);
    f = AddM(f, v);

    f = AddM(f, u);

    /* update the state */
    for(int i = 0; i < 15; ++i) {
        LFSR_S[i] = LFSR_S[i + 1];
    }
    LFSR_S[15] = f;
}

/* LFSR with work mode */
void ZUC::LFSRWithWorkMode() {
    unsigned int f, v;

    f = LFSR_S[0];
    v = MulByPow2(LFSR_S[0], 8);
    f = AddM(f, v);

    v = MulByPow2(LFSR_S[4], 20);
    f = AddM(f, v);

    v = MulByPow2(LFSR_S[10], 21);
    f = AddM(f, v);

    v = MulByPow2(LFSR_S[13], 17);
    f = AddM(f, v);

    v = MulByPow2(LFSR_S[15], 15);
    f = AddM(f, v);

    /* update state */
    for(int i = 0; i < 15; ++i) {
        LFSR_S[i] = LFSR_S[i + 1];
    }
    LFSR_S[15] = f;
}

/* Bit Reorganization Procedure */
void ZUC::BitReorganization() {
    BRC_X[0] = ((LFSR_S[15] & 0x7FFF8000) << 1) | (LFSR_S[14] & 0xFFFF);
    BRC_X[1] = ((LFSR_S[11] & 0xFFFF) << 16) | (LFSR_S[9] >> 15);
    BRC_X[2] = ((LFSR_S[7] & 0xFFFF) << 16) | (LFSR_S[5] >> 15);
    BRC_X[3] = ((LFSR_S[2] & 0xFFFF) << 16) | (LFSR_S[0] >> 15);
}

#define ROT(a, k) (((a) << k) | ((a) >> (32 - k)))

/* linear transformation L1 */
unsigned int ZUC::L1(unsigned int X) {
    return (X ^ ROT(X, 2) ^ ROT(X, 10) ^ ROT(X, 18) ^ ROT(X, 24));
}

/* linear transformation L2 */
unsigned int ZUC::L2(unsigned int X) {
    return (X ^ ROT(X, 8) ^ ROT(X, 14) ^ ROT(X, 22) ^ ROT(X, 30));
}

/* create 32-bit word */
#define MAKEU32(a, b, c ,d) (\
((unsigned int)(a) << 24) \
| ((unsigned int)(b) << 16) \
| ((unsigned int)(c) << 8) \
| ((unsigned int)(d)))


/* non-linear function F */
unsigned int ZUC::F(void) {
    unsigned int W, W1, W2, u, v;

    W = (BRC_X[0] ^ F_R1) + F_R2;
    W1 = F_R1 + BRC_X[1];
    W2 = F_R2 ^ BRC_X[2];
    u = L1((W1 << 16) | (W2 >> 16));
    v = L2((W2 << 16) | (W1 >> 16));
    F_R1 = MAKEU32(S0[u >> 24], S1[(u >> 16) & 0xFF], S0[(u >> 8) & 0xFF], S1[u & 0xFF]);
    F_R2 = MAKEU32(S0[v >> 24], S1[(v >> 16) & 0xFF], S0[(v >> 8) & 0xFF], S1[v & 0xFF]);

    return W;
}

#define MAKEU31(a, b, c) ( \
    ((unsigned int)((unsigned int)(0) \
    | (unsigned char)(a)) << 23) \
    | ((unsigned int)(b) << 8) \
    | (unsigned int)((unsigned int)(0) \
    | (unsigned char)(c)))


void ZUC::Initialization(unsigned char *k, unsigned char *iv) {
    unsigned int w;

    /* expand key */
    for(int i = 0; i < 16; ++i) {
        LFSR_S[i] = MAKEU31(k[i], EK_d[i], iv[i]);
    }
    /* set F_R1 and F_R2 to zero */
    F_R1 = 0;
    F_R2 = 0;	
    unsigned int nCount = 32;
    while (nCount > 0){
        BitReorganization();
        w = F();
        LFSRWithInitializationMode(w >> 1);
        nCount--;
    }

    BitReorganization();
    F();
    LFSRWithWorkMode();
}

void ZUC::GenerateKeyStream(unsigned int *pKeyStream, unsigned int KeyStreamLen){
    /* working cycles */
    for (unsigned int i = 0; i < KeyStreamLen; ++i){
        BitReorganization();
        pKeyStream[i] = F() ^ BRC_X[3];
        LFSRWithWorkMode();
    }
}
